Pressure Transfer Sleeve for Top-Slip Retention in Frac Plugs
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Solution Overview
Problem
Frac plugs often become dislodged at inappropriate times during hydraulic fracturing operations, leading to uncertainty about their effectiveness and requiring costly and time-consuming removal processes.
Innovation Solution
The isolation device features a pressure transfer sleeve that ensures top slips remain engaged with the casing during frac ball pump-down and fracturing, allowing the inner mandrel to be removed after setting, thereby enhancing plug reliability and reducing the risk of dislodgment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frac plugs are deployed to engage with casing slips, then zonal isolation is achieved, but the plugs may become dislodged at inappropriate times
Solution Approach 1:
The patent applies preliminary action by pre-positioning the pressure transfer sleeve within the plug assembly before deployment. The sleeve is designed to automatically engage and transfer pressure from the setting tool to the slips, ensuring proper engagement is achieved before the plug is released into the wellbore. This preliminary preparation prevents dislodgment by ensuring the slips are firmly engaged with the casing before any operational pressures are applied.
Solution Approach 2:
The pressure transfer sleeve acts as an intermediary component between the setting tool and the slips. It receives pressure from the setting tool and translates it into the mechanical force needed to firmly engage the slips with the casing. This intermediary mechanism ensures reliable force transmission while isolating the slips from direct exposure to fluctuating wellbore pressures, thereby preventing dislodgment.
2Reliability
If the inner mandrel remains in place to support the slips, then plug stability is maintained, but removal becomes time-consuming and costly
Solution Approach 1:
The patent applies the extraction principle by designing the inner mandrel as a separate, removable component that can be easily extracted from the plug assembly after the slips have been set and are firmly engaged with the casing. The pressure transfer sleeve remains in place to continue supporting the slips, while the mandrel is removed through a simple retrieval process. This separation allows the stable slip engagement to be maintained while eliminating the time-consuming removal of the entire plug assembly.
Solution Approach 2:
The plug assembly is segmented into distinct functional components: the inner mandrel, the pressure transfer sleeve, and the slips. This segmentation allows each component to be optimized independently - the mandrel can be removed for cost and time efficiency, while the pressure transfer sleeve remains to ensure continued slip engagement and plug stability. The segmented design enables selective retention of only the necessary components after setting.
3Reliability
If the pressure transfer sleeve is added to prevent dislodgment, then plug reliability is enhanced, but device complexity increases
Solution Approach 1:
The pressure transfer sleeve is designed as a multi-functional component that performs multiple roles: it transfers pressure from the setting tool to the slips during engagement, supports the slips after setting, and prevents dislodgment during operational pressures. By consolidating these functions into a single component rather than requiring separate mechanisms, the patent enhances reliability while minimizing the increase in device complexity.
Solution Approach 2:
The pressure transfer sleeve merges the functions of pressure transmission and mechanical support into a single integrated component. Rather than having separate pressure transmission mechanisms and slip support structures, the sleeve combines these functions, reducing the overall number of parts and simplifying the plug assembly while maintaining enhanced reliability and dislodgment prevention.
Data Source
AI summary
Disclosed herein are various embodiments of an isolation device comprising a top slip, a top slip prop in engagement with the top slip, a bottom slip, a bottom slip prop in engagement with the bottom slip, a packer element positioned between the top slip prop and the bottom slip prop, wherein movement of the top slip prop and the bottom slip prop towards each other causes the packer element to expand outwardly, an annular receptacle formed between the inner mandrel and the top slip prop, and a pressure transfer sleeve at least partially disposed within the annular receptacle.